Between 8 p.m. and 2 a.m. ET on New Year's Day, Shark Tank averaged 540,000 viewers and 240,000 adults 25-54 on the network. That's a six-year primetime high in the key news demo for a network that hit its fifth consecutive year of lows in 2013 -- as ratings continue to drop alongside interest in the financial crisis.

The 9 p.m. airing of Shark Tank actually marked CNBC's highest-rated program in three years, while the following hour brought its biggest audience in the same period of time.

The addition of Shark Tank, which will now marathon on Tuesdays starting at 8 p.m., is the latest move in CNBC's efforts to expand its alternative programming offerings. Those efforts included short-lived reality competition Crowd Rules in 2013, which followed a very similar formula to Shark Tank.

Shark Tank remains a huge boon to ABC, where it is currently airing its fifth season. The series regularly wins Friday nights for the broadcast network, averaging a 2.6 rating among adults 18-49 and 8.4 million viewers.